Reclining apparatus

Abstract

A compact and lightweight round reclining apparatus having a neutral position return function of automatically returning and securing the backrest to the preset neutral position when the backrest that has been reclined forward is raised is provided. A memory plate in approximately disc form having a center shaft at its center and a spring member for pressing the memory plate so that the memory plate always rotates in one direction intervene between a base plate and a gear plate. A guide portion, which is a long hole in approximately arc form, for restricting the movement of the lock gear outward in the direction of the radius through contact with the protrusion of the above described lock gear is provided inside the disc of the memory plate, and at least one notch is provided in the outer periphery of the memory plate so that an engaging portion provided on the above described gear plate enters into the notch and the memory plate is rotatable relative to the gear plate within the range of the notch.

1. A reclining apparatus comprising:
 a base plate in approximately disc form secured to either a seat cushion or a backrest of a seat; 
 a gear plate in approximately disc form having internal cogs which is combined with the base plate so as to be rotatable and face the base plate; 
 a number of lock gears having external cogs which can engage with the internal cogs of said gear plate, which are placed within a guide portion made of at least a pair of protrusions provided in said base plate so as to be moveable in the direction of the radius in the base plate; 
 a cam for controlling the movement of said lock gear in the direction of the radius so that the lock gear engages with the internal cogs of the gear plate; 
 a spring for pressing said cam so that the cam rotates in such a direction that said lock gear engages with said internal cogs; 
 a lever plate which rotates together with said cam and engages with a protrusion provided in said lock gear so as to control the movement of the lock gear inward in the direction of the radius; 
 a center shaft which penetrates through approximately the center of said base plate and gear plate so as to be rotatable together with the cam; and 
 an operation member which is connected to the center shaft so as to rotate and drive the center shaft against the force of said spring, characterized in that 
 a memory plate in approximately disc form having said center shaft at the center and a spring member for pressing the memory plate in one direction so that the memory plate always rotates intervene between said base plate and gear plate, 
 a guide portion, which is a long hole in approximately arc form for restricting the movement of the lock gear outwards in the direction of the radius through contact with the protrusion of said lock gear, is provided inside the disc of the memory plate, 
 at least one notch is provided in the outer periphery of the memory plate so that an engaging portion provided in and protruding from said gear plate enters into the notch and the memory plate is rotatable relative to the gear plate within the range of the notch, 
 when the backrest is in a range from the most forward reclined position to the highest raised position, the protrusion of said lock gear makes contact with said guide portion so as to form a lock free range where the external cogs of the lock gear are released from the engagement with the internal cogs of the gear plate, 
 when the backrest is in a range from the highest raised position to the most backward reclined position, the protrusion of said lock gear is released from making contact with said guide portion so as to form a range of the adjustment where the external cogs of the lock gear engage with the internal cogs of the gear plate, 
 said spring member presses the memory plate so that the memory plate rotates in such a direction that the protrusion of the lock gear disengages from the guide portion, and 
 when the backrest is reclined backward in a state where the protrusion of said lock gear makes contact with the guide portion of said memory plate, the memory plate rotates together with the base plate against the force of said spring members so that the protrusion of said lock gear is released from making contact with said guide portion and the external cogs of the lock gear engage with the internal cogs of the gear plate. 
 
   
   
     2. The reclining apparatus according to  claim 1 , characterized in that
 said gear plate is formed in approximately bowl form having steps in stair form, in which a first step where said internal cogs are formed around the inner periphery of the opening, a second step of which the radius of the circumference is smaller than that of the first step and which slides against the outer periphery of said lever plate, and a third step of which the radius of the circumference is smaller than that of the second step and which slides against the outer periphery of said memory plate are formed, and said spring member is provided between the memory plate and the gear plate. 
 
   
   
     3. The reclining apparatus according to  claims 1 , characterized in that
 an arc portion where no internal cogs are formed is provided in said gear plate, and this arc portion is thicker in the direction of the radius than the internal cogs portions, 
 an inclined portion, which inclines outward in the direction of the radius, is provided in an end portion of the guide portion provided in said memory plate, and 
 when the backrest is reclined forward within said lock free range, the external cogs of the lock gear ride on said arc portion, and after that, the protrusion of the lock gear is moved towards the center along the radius by said inclined portion so as to be guided to and make contact with the guide portion. 
 
   
   
     4. The reclining apparatus according to  claim 1 , characterized in that
 the periphery which reaches the end portion of said guide portion protrudes towards the center from the arc of the guide portion having the center shaft at the center. 
 
   
   
     5. A reclining apparatus comprising:
 a base plate in approximately disc form secured to either a seat cushion or a backrest of a seat; 
 a gear plate in approximately disc form having internal cogs which is combined with the base plate so as to be rotatable and face the base plate; 
 a number of lock gears having external cogs which can engage with the internal cogs of said gear plate, which are placed within a guide portion made of at least a pair of protrusions provided in said base plate so as to be moveable in the direction of the radius in the base plate; 
 a cam for controlling the movement of said lock gear in the direction of the radius so that the lock gear engages with the internal cogs of the gear plate; 
 a spring for pressing said cam so that the cam rotates in such a direction that said lock gear engages with said internal cogs; 
 a lever plate which rotates together with said cam and engages with a protrusion provided in said lock gear so as to control the movement of the lock gear inward in the direction of the radius; 
 a center shaft which penetrates through approximately the center of said base plate and gear plate so as to be rotatable together with the cam; and 
 an operation member which is connected to the center shaft so as to rotate and drive the center shaft against the force of said spring, characterized in that 
 a memory plate in approximately ring form having said center shaft at the center and a spring member for pressing the memory plate in one direction so that the memory plate always rotates intervene between said base plate and gear plate, 
 a guide portion in approximately arc form for restricting the movement of the lock gear outwards in the direction of the radius through contact with the protrusion of said lock gear is formed in the inner peripheral portion of the ring of the memory plate, 
 at least one notch is provided in the outer periphery of the memory plate so that an engaging portion provided in and protruding from said gear plate enters into the notch and the memory plate is rotatable relative to the gear plate within the range of the notch, 
 when the backrest is in a range from the most forward reclined position to the highest raised position, the protrusion of said lock gear makes contact with said guide portion so as to form a lock free range where the external cogs of the lock gear are released from the engagement with the internal cogs of the gear plate, 
 when the backrest is in a range from the highest raised position to the most backward reclined position, the protrusion of said lock gear is released from making contact with said guide portion so as to form a range of the adjustment where the external cogs of the lock gear engage with the internal cogs of the gear plate, 
 said spring member presses the memory plate so that the memory plate rotates in such a direction that the protrusion of the lock gear disengages from the guide portion, and 
 when the backrest is reclined backward in a state where the protrusion of said lock gear makes contact with the guide portion of said memory plate, the memory plate rotates together with the base plate against the force of said spring members so that the protrusion of said lock gear is released from making contact with said guide portion and the external cogs of the lock gear engage with the internal cogs of the gear plate. 
 
   
   
     6. The reclining apparatus according to  claim 5 , characterized in that
 said gear plate is formed in approximately bowl form having steps in stair form, in which a first step where said internal cogs are formed around the inner periphery of the opening, a second step of which the radius of the circumference is smaller than that of the first step and which slides against the outer periphery of said lever plate, and a third step of which the radius of the circumference is smaller than that of the second step and which slides against the outer periphery of said memory plate are formed, 
 said spring member is a spiral spring in such a form that the end on the outer side of the spiral is bent backward in the direction opposite to the direction in which the spiral winds and the end on the center side is bent in the same direction as the direction in which the spiral winds, where the end on the outer side engages with a hook portion in hook form provided on the inner periphery of said memory plate and the end on the center side engages with a protrusion in approximately columnar form provided in the bottom portion of the gear plate, and 
 said spiral spring is placed in said third step.